"It was very bitter. It's definitely not the way I wanted to win," Cilic said.

"I can't change it, but I'm really sorry for the fans that it finished like this."

Tournament director Chris Kermode told BBC Sport that officials had been left with no other option than to default Nalbandian.

"David is struggling to come to terms with it. He clearly regrets what happened -- but these things happen.

"Queen's is sold out and the spectators are watching some great tennis, so to have the match end this way is quite disappointing.

"But there's not a lot we can do about it. We are under the governance of ATP rules."

Kermode added that McDougall had been taken to the tournament's medical center to have attention for his injured leg.

An ATP official later told CNN that in their records dating back to 1980 they could not find another instance of a player being disqualified in an ATP final for a similar offense than committed by Nalbandian.